The present invention relates to a motor, and in particular to a closed magnetization circuit formed by the casing which holds the rotating motor shaft at axially opposed sides of the rotor. This arrangement has the following advantages compared to traditional motors:
(1) the rotor can be exposed for better heat dissipation;
(2) the overall height of the motor can be reduced;
(3) the weight and cost of the motor can be reduced;
(4) the surface of the exposed rotor can directly form a driving element for certain applications.